Organo-Auxin Herbicides

By Jennifer Bearden

Regardless of whether you are a homeowner, land manager or farmer; when you spray an herbicide, you are a pesticide applicator and must follow certain rules.  One of them is the Florida Organo-Auxin Herbicide Rule 5E-2.033.  Organo-auxin herbicides are very volatile and can drift onto off-target plants if not managed properly.  Tomato plants are especially sensitive to organo-auxin herbicides.

The bottom line of the rule is that if you use these herbicides, you must take certain precautions to minimize drift potential.  The following active ingredients are classified as organo-auxin herbicides:    2,4-D; 2,4,5-T; silvex; MCPA; 2,4-DP; MCPP; MCPB; dicamba; and triclopyr.

If you use one of these common herbicides, you are required to measure the wind speed and direction before you start spraying and once every hour while spraying.  For areas less than 5 acres in size, you should record and retain this information.  If you spray more than 5 acres, you MUST record and retain for at least 2 years the following information:

a. Name and address of the owner, lessee or tenant in control of the land, and the name and address of the applicator.

b. Location of the site to be treated, location of the herbicide mixing and loading area and description of application equipment used.

c. Date and time of application.

d. Trade name, manufacturer, formulation, total amount of product to be applied per acre and the amount of active ingredient of the product applied per acre.

e. Total acreage and crop or site treated.

f. Average hourly wind speed and direction.

g. Nozzle type including gallons per minute rating at specified pressure (usually 40 psi) and angle of spray emission if applicable.

Sprayer equipment should be adjusted to increase the droplet size coming out of the sprayer nozzles.  The larger the droplet, the less distance it will travel. Application pressures cannot exceed 35 pound per square inch.  You must also stop spraying if wind speed is over 10 miles per hour.

The Florida Organo-Auxin Herbicide Rule is designed to reduce the risk of herbicide drifting onto someone else’s commercially produced plants and causing irreparable damage to their crop.  It’s all about being good neighbors.

For more information about the Florida Organo-Auxin Herbicide Rule, go to or

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